I can't say I underrstand your question, but an example of 'conversion' might be this: in the '70s and '80s booksellers started selling related books together in a box. They called the product a 'boxed set' (in which the verb 'box' had the past tense marker '-ed'). But it's easier to say 'box set' (avoiding the tricky /-tst-/ cluster), and this converted form (in which 'box' has reverted to being a noun that behaves like an adjective) is becoming more popular. Google hits for -ed still outnumber it by about 3 to 1 world-wide, but it's still a substantial number, and on UK-only sites the balance is much closer.
- For Teachers